Remove Watermark in PowerPoint using C#. For more details: https://kb.aspose.com/slides/net/remove-watermark-in-powerpoint-using-csharp/

Remove Watermark in PowerPoint using C#.cs

using System;
using Aspose.Slides;
using Aspose.Slides.Export;

class Program
{
    static void Main(string[] args) // Remove watermark in slide using C#
    {
        new Aspose.Slides.License().SetLicense("License.lic");

        Presentation pres = new Presentation("WithWatermark.pptx");
        foreach (var slide in pres.Slides)
        {
            for (int i = 0; i < slide.Shapes.Count; i++)
            {
                AutoShape shape = (AutoShape)slide.Shapes[i];
                if(shape.Name == "watermark")
                {
                    slide.Shapes.Remove(shape);
                }
            }
        }
        pres.Save("WithoutWatermark.pptx", SaveFormat.Pptx);

        Console.WriteLine("Done");
    }
}